* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    color-scheme: dark;
    --primary: #6366f1;
    --primary-light: #818cf8;
    --bg-dark: #0f172a;
    --bg-card: #1e293b;
    --text-primary: #f1f5f9;
    --text-secondary: #94a3b8;
    --border: #334155;
    --gradient: linear-gradient(135deg, #6366f1, #8b5cf6, #a78bfa);
    --nav-bg: rgba(15, 23, 42, 0.85);
    --section-alt-bg: rgba(30, 41, 59, 0.3);
    --input-bg: rgba(30, 41, 59, 0.6);
    --input-border: #475569;
    --card-shadow: 0 20px 40px rgba(0, 0, 0, 0.3);
}

/* Light theme */
[data-theme="light"] {
    /* 注意：此处刻意不声明 color-scheme:light。
       鸿蒙浏览器「深色模式跟随系统」会对网页做算法级颜色转换，且仅转换
       未声明支持深色配色方案的页面（华为 ArkWeb 官方文档）。
       因此全局恒定保持 color-scheme:dark（见 :root），让亮色主题的色值
       也被算法豁免、不被压暗。副作用：亮色主题下原生滚动条/下拉框呈
       暗色样式，属可接受的代价。 */
    --bg-dark: #f8fafc;
    --bg-card: #ffffff;
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --border: #e2e8f0;
    --nav-bg: rgba(248, 250, 252, 0.9);
    --section-alt-bg: rgba(241, 245, 249, 0.8);
    --input-bg: #ffffff;
    --input-border: #cbd5e1;
    --card-shadow: 0 20px 40px rgba(0, 0, 0, 0.08);
}

html {
    scroll-behavior: smooth;
}

section[id] {
    scroll-margin-top: 80px;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
    background: var(--bg-dark);
    color: var(--text-primary);
    line-height: 1.6;
    overflow-x: hidden;
    transition: background 0.3s, color 0.3s;
}

/* ===== Navigation ===== */
nav {
    position: fixed;
    top: 0;
    width: 100%;
    padding: 1rem 2rem;
    background: var(--nav-bg);
    -webkit-backdrop-filter: blur(20px);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border);
    z-index: 1000;
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: nowrap;
    transition: background 0.3s, border-color 0.3s;
}

.nav-logo {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 1.25rem;
    font-weight: 700;
    background: var(--gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.nav-logo-img {
    width: 32px;
    height: 32px;
    border-radius: 6px;
    object-fit: contain;
    -webkit-text-fill-color: initial;
}

.nav-links {
    display: flex;
    gap: 2rem;
    list-style: none;
}

.nav-links a {
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 0.9rem;
    transition: all 0.3s;
    padding: 0.4rem 0;
    position: relative;
}

.nav-links a::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--gradient);
    transition: width 0.3s;
}

.nav-links a:hover,
.nav-links a.active {
    color: var(--text-primary);
}

.nav-links a.active::after {
    width: 100%;
}

/* 管理后台入口链接（原为内联硬编码色值） */
.nav-links a.admin-link {
    color: var(--primary);
}

.nav-actions {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    flex-shrink: 0;
}

/* Theme Toggle */
.theme-toggle {
    width: 36px;
    height: 36px;
    border-radius: 50%;
    border: 1px solid var(--border);
    background: transparent;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.1rem;
    color: var(--text-secondary);
    transition: all 0.3s;
}

.theme-toggle:hover {
    border-color: var(--primary);
    color: var(--primary);
}

.theme-icon-dark { display: none; }
.theme-icon-light { display: inline; }
[data-theme="light"] .theme-icon-dark { display: inline; }
[data-theme="light"] .theme-icon-light { display: none; }

.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    cursor: pointer;
    background: transparent;
    border: none;
    padding: 0;
}

.nav-toggle span {
    width: 24px;
    height: 2px;
    background: var(--text-primary);
    transition: transform 0.3s, opacity 0.3s, background 0.3s;
    transform-origin: center;
}
.nav-toggle.active span:nth-child(1) {
    transform: translateY(7px) rotate(45deg);
}
.nav-toggle.active span:nth-child(2) {
    opacity: 0;
}
.nav-toggle.active span:nth-child(3) {
    transform: translateY(-7px) rotate(-45deg);
}

/* ===== Hero Section ===== */
.hero {
    min-height: 100vh;
    min-height: 100svh;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    padding: 6rem 2rem 4rem;
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 600px;
    height: 600px;
    background: radial-gradient(circle, rgba(99, 102, 241, 0.15) 0%, transparent 70%);
    border-radius: 50%;
    pointer-events: none;
}

.hero-content {
    max-width: 800px;
    position: relative;
}

.hero-badge {
    display: inline-block;
    padding: 0.5rem 1.25rem;
    background: rgba(99, 102, 241, 0.1);
    border: 1px solid rgba(99, 102, 241, 0.3);
    border-radius: 50px;
    font-size: 0.85rem;
    color: var(--primary-light);
    margin-bottom: 2rem;
}

.hero h1 {
    font-size: 3.5rem;
    font-weight: 800;
    line-height: 1.2;
    margin-bottom: 1.5rem;
}

.hero h1 .highlight {
    background: var(--gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero p {
    font-size: 1.2rem;
    color: var(--text-secondary);
    margin-bottom: 2.5rem;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.hero-buttons {
    display: flex;
    gap: 1rem;
    justify-content: center;
    flex-wrap: wrap;
}

.btn {
    padding: 0.875rem 2rem;
    border-radius: 12px;
    font-size: 1rem;
    font-weight: 600;
    text-decoration: none;
    transition: all 0.3s;
    cursor: pointer;
}

.btn-primary {
    background: var(--gradient);
    color: white;
    border: none;
    box-shadow: 0 4px 20px rgba(99, 102, 241, 0.3);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 30px rgba(99, 102, 241, 0.4);
}

.btn-outline {
    background: transparent;
    color: var(--text-primary);
    border: 1px solid var(--border);
}

.btn-outline:hover {
    border-color: var(--primary);
    background: rgba(99, 102, 241, 0.05);
}

/* ===== Stats ===== */
.stats {
    display: flex;
    justify-content: center;
    gap: 4rem;
    margin-top: 4rem;
    padding-top: 3rem;
    border-top: 1px solid var(--border);
}

.stat-item {
    text-align: center;
}

.stat-number {
    font-size: 2rem;
    font-weight: 800;
    background: var(--gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.stat-label {
    font-size: 0.85rem;
    color: var(--text-secondary);
    margin-top: 0.25rem;
}

/* ===== Services ===== */
.services {
    padding: 6rem 2rem;
    max-width: 1200px;
    margin: 0 auto;
}

.section-header {
    text-align: center;
    margin-bottom: 4rem;
}

.section-tag {
    font-size: 0.85rem;
    color: var(--primary-light);
    text-transform: uppercase;
    letter-spacing: 2px;
    margin-bottom: 1rem;
}

.section-header h2 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
}

.section-header p {
    color: var(--text-secondary);
    max-width: 600px;
    margin: 0 auto;
}

.services-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 2rem;
}

.service-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 20px;
    padding: 2.5rem;
    transition: all 0.3s;
    position: relative;
    overflow: hidden;
}

.service-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: var(--gradient);
    opacity: 0;
    transition: opacity 0.3s;
}

.service-card:hover {
    transform: translateY(-5px);
    border-color: rgba(99, 102, 241, 0.3);
    box-shadow: var(--card-shadow);
}

.service-card:hover::before {
    opacity: 1;
}

.service-icon {
    width: 56px;
    height: 56px;
    background: rgba(99, 102, 241, 0.1);
    border-radius: 14px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    margin-bottom: 1.5rem;
}

.service-card h3 {
    font-size: 1.25rem;
    margin-bottom: 0.75rem;
}

.service-card p {
    color: var(--text-secondary);
    font-size: 0.95rem;
    line-height: 1.7;
}

.service-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin-top: 1.5rem;
}

.service-tags span {
    padding: 0.3rem 0.75rem;
    background: rgba(99, 102, 241, 0.08);
    border-radius: 6px;
    font-size: 0.8rem;
    color: var(--primary-light);
}

/* ===== Process ===== */
.process {
    padding: 6rem 2rem;
    background: var(--section-alt-bg);
    transition: background 0.3s;
}

.process-content {
    max-width: 1000px;
    margin: 0 auto;
}

.process-steps {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 2rem;
    margin-top: 4rem;
}

.step {
    text-align: center;
    position: relative;
}

.step-number {
    width: 48px;
    height: 48px;
    background: var(--gradient);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 1.1rem;
    margin: 0 auto 1.25rem;
    color: white;
}

.step h4 {
    font-size: 1.05rem;
    margin-bottom: 0.5rem;
}

.step p {
    font-size: 0.85rem;
    color: var(--text-secondary);
}

/* ===== Tech Stack ===== */
.tech {
    padding: 6rem 2rem;
    max-width: 1000px;
    margin: 0 auto;
}

.tech-grid {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 1rem;
    margin-top: 3rem;
}

.tech-item {
    padding: 0.75rem 1.5rem;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 10px;
    font-size: 0.9rem;
    transition: all 0.3s;
}

.tech-item:hover {
    border-color: var(--primary);
    background: rgba(99, 102, 241, 0.05);
}

/* ===== Contact ===== */
.contact {
    padding: 6rem 2rem;
    background: var(--section-alt-bg);
    transition: background 0.3s;
}

.contact-content {
    max-width: 700px;
    margin: 0 auto;
    text-align: center;
}

.contact-cards {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 1.5rem;
    margin-top: 3rem;
}

.contact-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 16px;
    padding: 2rem 1.5rem;
    text-align: center;
    transition: all 0.3s;
}

.contact-card:hover {
    border-color: rgba(99, 102, 241, 0.3);
}

.contact-card .icon {
    font-size: 2rem;
    margin-bottom: 1rem;
}

.contact-card h4 {
    font-size: 0.9rem;
    color: var(--text-secondary);
    margin-bottom: 0.5rem;
}

.contact-card p {
    font-size: 1rem;
    font-weight: 500;
}

/* ===== Message Form ===== */
.message-form {
    margin-top: 3rem;
    text-align: left;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 20px;
    padding: 2.5rem;
    transition: all 0.3s;
}

.message-form h3 {
    font-size: 1.3rem;
    margin-bottom: 0.5rem;
    text-align: center;
}

.form-subtitle {
    color: var(--text-secondary);
    font-size: 0.9rem;
    text-align: center;
    margin-bottom: 2rem;
}

.form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
    margin-bottom: 1rem;
}

.form-group {
    display: flex;
    flex-direction: column;
}

.form-group.full-width {
    margin-bottom: 1rem;
}

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 0.75rem 1rem;
    background: var(--input-bg);
    border: 1px solid var(--input-border);
    border-radius: 10px;
    color: var(--text-primary);
    font-size: 0.9rem;
    font-family: inherit;
    transition: border-color 0.3s;
    outline: none;
}

.form-group input::placeholder,
.form-group textarea::placeholder {
    color: var(--text-secondary);
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    border-color: var(--primary);
}

.form-group select {
    appearance: none;
    -webkit-appearance: none;
    cursor: pointer;
    background-image: url("data:image/svg+xml;charset=utf-8,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='8' viewBox='0 0 12 8'%3E%3Cpath d='M1 1l5 5 5-5' fill='none' stroke='%2394a3b8' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 14px center;
    background-size: 12px 8px;
    padding-right: 2.5rem;
}

.form-group textarea {
    resize: vertical;
    min-height: 100px;
}

/* Chrome 自动填充：覆盖浏览器强制的亮色背景，避免暗色主题下看不清 */
.form-group input:-webkit-autofill,
.form-group textarea:-webkit-autofill {
    -webkit-box-shadow: 0 0 0 1000px var(--input-bg) inset;
    -webkit-text-fill-color: var(--text-primary);
    transition: background-color 9999s ease-in-out 0s;
}

.form-submit {
    width: 100%;
    font-size: 1rem;
    margin-top: 0.5rem;
}

.form-msg {
    text-align: center;
    margin-top: 1rem;
    font-size: 0.9rem;
    min-height: 1.5em;
}

.form-msg.success {
    color: #22c55e;
}

.form-msg.error {
    color: #ef4444;
}

/* ===== Footer ===== */
footer {
    padding: 2rem;
    text-align: center;
    border-top: 1px solid var(--border);
    color: var(--text-secondary);
    font-size: 0.85rem;
    transition: border-color 0.3s;
}

footer a {
    color: var(--text-secondary);
    text-decoration: none;
    transition: color 0.3s;
}

footer a:hover {
    color: var(--primary);
}

/* ===== Animations ===== */
.fade-in {
    opacity: 0;
    transform: translateY(30px);
    transition: all 0.8s ease;
}

.fade-in.visible {
    opacity: 1;
    transform: translateY(0);
}

/* ===== Responsive ===== */
@media (max-width: 768px) {
    .back-to-top {
        bottom: 104px !important; /* 与客服按钮间距同 PC 端 28px: 20+56+28=104 */
        bottom: calc(104px + env(safe-area-inset-bottom)) !important;
        right: 14px !important; /* 与客服按钮(56px/right:10px)圆心对齐: 10+28-24=14 */
    }
    /* Logo: 默认显示图标+文字 */
    .nav-logo {
        gap: 0.4rem;
    }
    .nav-logo span {
        font-size: 1rem;
        white-space: nowrap;
    }
    /* 菜单展开时，整个Logo隐藏 */
    nav.menu-open .nav-logo {
        display: none !important;
    }
    .nav-links {
        display: none;
        flex-wrap: nowrap;
        gap: 0.5rem;
    }
    .nav-links.mobile-open {
        display: flex;
        flex-direction: row;
        flex-wrap: nowrap;
        background: var(--nav-bg);
        -webkit-backdrop-filter: blur(20px);
        backdrop-filter: blur(20px);
        padding: 0 0.5rem;
        justify-content: center;
        align-items: center;
    }
    .nav-links.mobile-open a {
        font-size: 0.8rem;
        padding: 0.3rem 0;
    }
    .nav-toggle {
        display: flex;
    }

    .hero h1 {
        font-size: 2.25rem;
    }

    .hero p {
        font-size: 1rem;
    }

    .stats {
        gap: 2rem;
    }

    .services-grid {
        grid-template-columns: 1fr;
    }

    .process-steps {
        grid-template-columns: repeat(2, 1fr);
    }

    .contact-cards {
        grid-template-columns: 1fr;
    }

    .form-row {
        grid-template-columns: 1fr;
    }

    /* 移动端输入字号提到 16px，防止 iOS Safari 聚焦时强制缩放页面 */
    .form-group input,
    .form-group select,
    .form-group textarea {
        font-size: 16px;
    }
}

@media (max-width: 480px) {
    .hero h1 {
        font-size: 1.8rem;
    }

    .stats {
        flex-direction: column;
        gap: 1.5rem;
    }

    .process-steps {
        grid-template-columns: 1fr;
    }
}

/* ===== Back to Top ===== */
.back-to-top {
    position: fixed;
    bottom: 128px;
    right: 28px;
    width: 48px;
    height: 48px;
    background: linear-gradient(135deg, #6366f1, #8b5cf6);
    border: none;
    padding: 0;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    opacity: 0;
    visibility: hidden;
    transform: translateY(20px);
    transition: all 0.3s ease;
    box-shadow: 0 4px 15px rgba(99, 102, 241, 0.4);
    z-index: 999;
    font-size: 1.2rem;
    color: white;
    filter: opacity(0.55);
    transition: all 0.3s ease, filter 0.3s ease;
}
.back-to-top:hover {
    filter: opacity(1);
}
.back-to-top.visible {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

/* ===== PC Only (隐藏移动端) ===== */
.pc-only {
    display: list-item;
}

@media (max-width: 768px) {
    .pc-only {
        display: none !important;
    }
}

/* ===== 强制深色硬编码防护（华为/鸿蒙浏览器对策）=====
   已确诊（2026-08-29 真机验证）：鸿蒙浏览器「深色模式跟随系统」时在渲染层
   对网页做算法级颜色转换（Chromium 色值转换算法，高亮度压暗、低亮度不变），
   发生在全部 CSS 结算之后，CSS 层面无法对抗。本段为保险性定色；
   真正的对策是上方 :root 恒定的 color-scheme:dark 声明——
   按华为 ArkWeb 文档，声明支持深色配色方案的网页色值不被转换。 */

/* --- 默认暗色主题 --- */
body {
    background-color: #0f172a !important;
    background-image: linear-gradient(#0f172a, #0f172a) !important;
}
body::before {
    content: '';
    position: fixed;
    top: 0; left: 0; right: 0; bottom: 0;
    background: #0f172a;
    z-index: -99999;
    pointer-events: none;
}

nav, .nav-links.mobile-open {
    background-color: rgba(15, 23, 42, 0.85) !important;
    background-image: linear-gradient(rgba(15, 23, 42, 0.85), rgba(15, 23, 42, 0.85)) !important;
}

.service-card, .tech-item, .contact-card, .message-form {
    background-color: #1e293b !important;
    background-image: linear-gradient(#1e293b, #1e293b) !important;
}

.process, .contact {
    background-color: rgba(30, 41, 59, 0.3) !important;
    background-image: linear-gradient(rgba(30, 41, 59, 0.3), rgba(30, 41, 59, 0.3)) !important;
}

.form-group input, .form-group select, .form-group textarea {
    background-color: rgba(30, 41, 59, 0.6) !important;
    background-image: linear-gradient(rgba(30, 41, 59, 0.6), rgba(30, 41, 59, 0.6)) !important;
}

.nav-toggle span {
    background-color: #f1f5f9 !important;
    background-image: linear-gradient(#f1f5f9, #f1f5f9) !important;
}

.hero-badge, .service-icon {
    background-color: rgba(99, 102, 241, 0.1) !important;
    background-image: linear-gradient(rgba(99, 102, 241, 0.1), rgba(99, 102, 241, 0.1)) !important;
}

.service-tags span {
    background-color: rgba(99, 102, 241, 0.08) !important;
    background-image: linear-gradient(rgba(99, 102, 241, 0.08), rgba(99, 102, 241, 0.08)) !important;
}

.btn-outline:hover, .tech-item:hover {
    background-color: rgba(99, 102, 241, 0.05) !important;
    background-image: linear-gradient(rgba(99, 102, 241, 0.05), rgba(99, 102, 241, 0.05)) !important;
}

/* --- 亮色主题硬编码覆盖 --- */
[data-theme="light"] body {
    background-color: #f8fafc !important;
    background-image: linear-gradient(#f8fafc, #f8fafc) !important;
}
[data-theme="light"] body::before {
    background: #f8fafc;
}

[data-theme="light"] nav, [data-theme="light"] .nav-links.mobile-open {
    background-color: rgba(248, 250, 252, 0.9) !important;
    background-image: linear-gradient(rgba(248, 250, 252, 0.9), rgba(248, 250, 252, 0.9)) !important;
}

[data-theme="light"] .service-card, [data-theme="light"] .tech-item, [data-theme="light"] .contact-card, [data-theme="light"] .message-form {
    background-color: #ffffff !important;
    background-image: linear-gradient(#ffffff, #ffffff) !important;
}

[data-theme="light"] .process, [data-theme="light"] .contact {
    background-color: rgba(241, 245, 249, 0.8) !important;
    background-image: linear-gradient(rgba(241, 245, 249, 0.8), rgba(241, 245, 249, 0.8)) !important;
}

[data-theme="light"] .form-group input, [data-theme="light"] .form-group select, [data-theme="light"] .form-group textarea {
    background-color: #ffffff !important;
    background-image: linear-gradient(#ffffff, #ffffff) !important;
}

[data-theme="light"] .nav-toggle span {
    background-color: #1e293b !important;
    background-image: linear-gradient(#1e293b, #1e293b) !important;
}

/* ===== 无障碍：尊重用户的减少动态偏好 ===== */
@media (prefers-reduced-motion: reduce) {
    html {
        scroll-behavior: auto;
    }
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}